1. Field
The following description relates to an agent for reducing graphene oxide, and a method of preparing reduced graphene oxide using the same, and to, for example, an agent for reducing graphene oxide that is a mixture of a reducing agent containing a halogen element with CF3COOH, and a method of preparing reduced graphene oxide using the same.
2. Description of Related Art
Since graphene has a hexagonal structure, in which carbons are connected to one another by conjugate bonds, it exhibits high conductivity and charge mobility. Thus, graphene is a material having great future applicability. Researchers have been actively conducting researches to apply graphene that exists in the nature to various electronic and high-tech applications. A single graphene molecule has a planar sheet structure of sp2-bonded carbon atoms that are densely packed in a honeycomb lattice. In order to use graphene in various applications, it is necessary to produce a large quantity of graphene comprising a single layer or multiple layers that are not a lump of graphene.
In order to prepare graphene including a single layer or multiple layers, a preparing method that involves a reduction of graphene oxide compound is often used. According to the method, graphene oxide is first obtained by using a sticky tape method or by oxidizing a lump of graphene. Thereafter, the formed graphene oxide is dispersed in a solvent, applied to a device in accordance with its purpose of use, and then reduced to exhibit graphene characteristics again.
As a method for producing graphene or reduced graphene oxide by reducing graphene oxide, there are various known methods that use reducing agents such as hydrazine hydrate, sodium borohydrate (NaBH4), sulfuric acid (H2SO4), and so on. However, such graphene synthesis methods involve issues with respect to restriction in the use of a reducing agent, low efficiency, impurities included in the final product, and the like. Thus, with these methods, it is difficult to mass-produce graphene by reducing graphene oxide.
For example, until now, reduced graphene oxide obtained by using a reducing agent such as hydrazine hydrate has been known as having the highest purity. The reduced graphene oxide (RGO) obtained with hydrazine hydrate has a carbon/oxygen element ratio of 8 to 12 and contains nitrogen. The nitrogen element acts as an impurity in graphene, and it is not easy to remove the nitrogen element from graphene obtained by reducing graphene oxide using hydrazine hydrate. Due to the existence of the nitrogen element acting as an impurity, it is difficult to obtain a desired electron transfer phenomenon with the reduced graphene oxide. Thus, it is necessary to remove the nitrogen element.
Further, in case of reducing graphene oxide by using reducing agents such as hydrazine hydrate, sodium borohydrate (NaBH4), sulfuric acid (H2SO4), and so on to obtain graphene, a reaction is performed at a high temperature. Thus, such a method cannot be applied to form graphene on a flexible substrate.